This invention generally relates to refrigeration system to be used in automobiles. More specifically, this invention relates to a liquid refrigerant separator that prevents condensation of liquid refrigerant in the compressor during off cycle when the engine is switched off.
Modern refrigerant compressor technology has generated designs which provide the maximum capacity per unit, weight, cost and efficiency. The compressors are generally designed for high rotative speeds and high bearing loads. In order to achieve these features it is important for these compressors not to have any liquid of any sort. Liquid can cause undue loads and NVH in the compressor chamber.
Liquid entering the cylinder can stem from two sources liquid oil can enter the cylinder from foaming of the oil in the compressor crankcase on start up. The other source of liquid is liquid refrigerant in relatively pure form, which can return under abnormal conditions through the suction or discharge lines.
If large quantities of liquid refrigerant enter the compressor much of the refrigerant will be entrapped into the cylinder with the vapor and will cause a condition known as slugging which accompanied by pounding and knocking sounds could cause compressor damage.
The liquid refrigerant can also return to the compressor in small quantities but over a period of time. This can happen in two ways. The first is when the refrigerant vapor condenses in the compressor over a prolonged period of time. The other way liquid refrigerant can enter the compressor is during start-ups. In order to prevent any liquid from entering the compressor, modern technology have developed suctions drums or surge accumulators whose sole purpose is to catch the liquid refrigerant returning in large or small quantities and prevent this potentially harmful liquid refrigerant from reaching the compressor. A suction accumulator is usually positioned between an evaporator and the compressor in an air conditioning unit. During operation, the suction accumulator receives the combined liquid and vapor from the evaporator via an inlet tube. Vapor passes on to the compressor via an outlet tube. Over the years various technologies have been developed to insure that only vapor passes through the suction tube and reaches the compressor. The suction accumulators prevent any liquid refrigerant from reaching the compressor.
However, when the system is turned off for a prolonged period, and the outdoor ambient temperature is less than the indoor ambient temperature, the compressor can become the coldest part of an air conditioning system. When this occurs, the refrigerant migrates to the compressor sometimes filling it completely with liquid refrigerant. Although modern technologies have devised systems to prevent any liquid refrigerant from reaching the compressor during use of the system, technology has yet to be developed to prevent any condensation of vapor refrigerant in the compressor when the system is turned off for a prolonged period of time.
Therefore there is a need for a refrigeration system that will prevent substantial condensation of a vapor refrigerant in the compressor when the system is turned off for a prolonged period of time.
Accordingly, this invention provides for a refrigeration system that prevents condensation of the liquid refrigerant in the compressor when the system is shut off for a prolonged period of time.
Briefly, the invention includes a compressor for compressing vapor refrigerant, a condenser for condensing liquid refrigerant discharged out of the compressor, an evaporator for converting liquid refrigerant into vapor refrigerant and an accumulator for preventing liquid refrigerant from reaching the compressor.
The refrigeration system includes a device for preventing condensation of liquid refrigerant in the compressor when the refrigeration is switched off for a prolonged period of time.
The device comprises a first reservoir that is a part of the conduit connecting the compressor and the accumulator. The first reservoir is placed below the body of the compressor and has a larger cross-section than the rest of the conduit.
The present invention also includes a second reservoir in the conduit connecting the compressor and the condenser. Like the first reservoir, the second reservoir is also placed below the body of the compressor.
The present invention also provides for a method of preventing condensation of the refrigerant in the compressor. When the refrigeration system is shut off the vapor present in the conduit condense in the conduit. As the refrigeration system continues to cool the liquid formed in the conduit will get collected in the reservoirs. Since the reservoirs are placed vertically below the compressor all of the liquid is collected in the reservoirs and prevented from traveling to the body of the compressor.